Please refer to the manpages of exports (man exports) for more options.

+

Please refer to the manpages of exports ('man exports' on the UCS master) for more options.

= See also =

= See also =

Revision as of 14:41, 1 October 2013

Note: This article is not yet reviewed.

Version 1.0

Note: Cool Solutions are articles documenting additional functionality based on Univention products.
Not all of the shown steps in the article are covered by Univention Support. For questions about your support coverage contact your contact person at Univention before you want to implement one of the shown steps.

Contents

Introduction

The default partitioning of a Univention Corporate Client separates user data and system data. This allows a complete replacement of the system image with a newer one without loosing user data or the domain join status. Usually, these images are distributed through a NFS share created automatically on the Univention Corporate Server that has the UCC-App installed.

In some cases one might not want to use a Univention Corporate Server to provide the NFS share. For example in a small branch office with very poor connection to the main office. Using an Univention Corporate Client as NFS server for the other UCCs might be an alternative that is described in this article. Since the free space is always limited on a thinclient, in such case one probably wants to use an USB pendrive containing the images.

Please note that this article does not take care of the PXE configuration. As this article addresses scenarios with small branch offices, we assume that the Univention Corporate Clients boot directly from harddisk (Local boot) and not via PXE. If that is not the case in your scenario, you need to adjust the PXE settings.Hint: You can follow UCC PXE rollout an replace the nfsroot= part with the IP adresse of the UCC-Image-Distribution-Server.

Recommended Procedure

The following steps need to be completed:

Install the designated UCC-Image-Distribution-Server with a normal UCC-Client Image

Create the NFS share and mount the USB pendrive

Specify the UCC-Image-Distribution-Server as server that holds the UCC-Image for the other Univention Corporate Clients

Make the UCC-thinclients update their system image from the UCC-Image-Distribution-Server

Install a Univention Corporate Client as Image-Distribution-Server

At first, we need to install the designated UCC-Image-Distribution-Server with a standard UCC-Image. This should be done according to the UCC manual. In the following we will assume that the official UCC thin client image is used.

After the installation is finished, log in to the UCC via ssh:

ssh root@ucc-image-server.univention.test

We need to disable the overlay filesystem and the read-only mode:

ucr set ucc/thinclientoverlayfs=false
ucr set ucc/boot/mount=rw

We assume that an USB pendrive is used to contain the image(s). So we need to create a directory to mount the USB pendrive and copy the images from the Univention Corporate Server that holds the original UCC images:

Note: While publishing this article, UCC 1.0 rev2 is the current version, so we use ucc-1.0-rev2-thinclient-image.img in the examples. If you want to use a different image, you need to adjust the image name accordingly.

Note: On an Univention Corporate Client with the official thin client image, the first USB device will always be /dev/sdb. If you don't use the official image or if you use more than one USB device, you need to replace sdb with the correct device name.

For upcoming reboots you probably want to add this to your /etc/fstab to make sure the USB pendrive gets mounted automatically:

/dev/sdb1 /var/lib/univention-client-boot ext4 defaults 0 0

Alternatively, it is also possible to use blkid for an unique identifier of a filesytem (block device).

Note: In this example we assume the filesystem is Ext4, please change the line to reflect the filesystem in your disk (vfat -for FAT32-, ntfs or ext3 are other typical examples).
Now we can install the NFS server components:

apt-get install nfs-common nfs-kernel-server

To configure the desired NFS share, append the following to /etc/exports:

Configure the image

The server that holds the image (assigned server) is specified at the LDAP object of the image. We need to change the assigned server using the Univention Directory Manager command line tool on an Univention Corporate Server Domaincontroller: